Carburetor



Nov. 14, 1933. M. E. CHANDLER GARBURETOR F m April 23, 1951 2 Sheets-Sheet 1 Rm ML W m C E N w m M Y A TTORNE Y.

Nov. 14, 1933. M, E. CHANDLER CARBURETOR Filed April 25, 1931 2 Sheets-Sheet 2 INVENTOR. Alf/fan 15 C/mnd/er Q fiaz a ATfORNEY Patented Nov. 14, 1933 CARBURETOR Milton E. Chandler, South Bend, Ind., assignor to Bendix Stromberg Carburetor Company, South Bend, Ind., a corporation of Illinois Application April 23, 1931. Serial No 532,233

9 Claims.

thermostat which is preferably situated above the fuel level where it .is more quickly responsive to the changes in temperature conditions.

Another feature of the invention'relates to the contour of the thermostatically actuated cam which preferably has a series of depressions provided in the cam surface for coacting with a complementary formed cam follower, thus effecting .the variations of fuel pumped by a series of graduated steps.

Another feature relates to a thermostatic control of a suction-operated pump wherein the charging or filling stroke is limited in accordance with temperature.

Other objects and features of the invention will be apparent from the following description of one illustrative embodiment which I have shown in the accompanying drawings, in which:

Figure 1 is a vertical cross-section of a portion of a carburetor showing the improved acceleration pump installed thereon;

Figure 2 is a view of the thermostatic control taken in the directions of the arrows 2--2 in Figure 1; and

Figure 3 is a diagrammatic showing of the carburetor.

Referring to the drawings, 10 is a carburetor body having a fuel reservoir 12, a jet 14 and a throttle valve 16.

The carburetor illustrated is of the down-draft type, although the invention is equally adaptable to either the down-draft or up-draft carburetors. It is desirable during the acceleration of a motor vehicle to momentarily supply an additional amount of fuel for enriching the mixture during the period of acceleration, and it is also desirable to reduce the supply as the temperature in creases, for under high temperatures, the need is lessened and in some cases the acceleration is reduced by an unregulated charge.

The fuel pump illustrated comprises a suctionoperated piston 18, closely fitting within a cylin der 20, that is connected to the mixing chamber on the discharge side of throttle valve 16 by a passage 22.

Within the cylinder 20 is preferably provided a'th'readed pin 24, which acts as a stop to adjust- 59 ably limit the downward movement of piston 18. On the under side of piston 18 is a helicalspring 26, which coacts with a cup member 28, and urges the piston toward the upper part of the cylinder. Lever 30, pivotally mounted on the body 10 by a screw 32, is connected to the piston 18 by a link 34, which preferably has a ball-and-socket connection with either the piston or lever, it being shown in the drawings'as having a balland-socket connection with the piston and a 7 movable pin connection with the lever.

The opposite end of lever 30 is connected by a similar link 36 to an inverted cylindrical cup member 38, within' which is a piston 40, slidably mounted upon a stem 42, having fuel discharge passage 44 that leads to a nozzle 43 in the mixing chamber. Piston 40 is preferably selected of a slightly smaller diameter than cylinder 38, and the cylinder which normally lies below the level of'the fuel, is filled on the upstroke by the so liquid fuel passing between the piston and cylinder. Piston 40 is urged to its upper position by a spring 46 and has a bevelled valve seat 50 at its upper end which coacts with the headed portion 52 of stem 42 to seal cross passage 54 35 and prevent fuel from entering the discharge passage 44. A spring-operated economizer valve 58 is also provided which has an upwardly pro-. jecting stem 60 adapted to contact with lever 30 on the downward stroke of the-' acceleration 9o pump and permit an added quantity of fuel to flow through passages 62 and valve seat 64 to other passages not shown whereby it is delivered to the mixing chamber in the ordinary manner.

Immediately above lever 30 is a thermostat 66 preferably formed of a coil of two jo'ined met als having different coefficients of expansion. One end of the thermostat is anchored at 68, and the opposite end is secured to a cam member 70 pivotally mounted on the carburetor body by 0 a pin 72. The contact surface of cam '70 is preferably provided with a series of notches 74 within which is received the end of a slidable cam follower 76, which contacts both with the rotary cam and lever 30.

In the operation of the pump, when the throttle is closed, the vacuum on the discharge side of the throttle will be increased and piston 18 will be drawn downwardly until it contacts with the stop screw 24, cylinder 38 will be drawn upwardly no to theposition shown in Figure 1 and will be filled with fuel from the fuel reservoir 12 in which the fuel normally stands above the top of the piston 40. The position shown in Figure 1 illus-- perature of the thermostat. When throttle 16 is suddenly opened, the pressure on thedischarge side of the throttle will be increased and piston 18 will be forced upwardly by the spring 26, depress cylinder 38 and force the fuel within the cylinder 38 to the mixing chamber. The amount of fuel discharged at each pump stroke will be limited by the quantity contained in cylinder 38 and this, as before stated, will be regulated by the thermostatically operated cam 70, which limits the upward travel of the cylinder through the medium of the cam follower '76.

Descent of cylinder 38 will cause piston 40 to be pushed downwardly against the force of spring 46 and open the valve seat 50, thereby permitting fuel to be discharged for a substantial period of time after cylinder 38 has reached its lowest position. Toward the end of the downward stroke of cylinder 38, lever 30 will contact with the head portion of pin 60 and open the economizer valve 58, which valve will remain open so long as the pressure transmitted to the cylinder 20 is insufficient to move the piston 18 downwardly against the tension of spring 26. It may be readily seen from the above description that I have provided an ac A celeration pump in which the amount of fuel discharged at each stroke is dependent on the temperature above the fuel reservoir and that the mechanism will limit the quantity of fuel within the pump cylinder which is discharged into the mixing chamber upon the opening of the throttle.

While I have illustrated and described a preferred embodiment of my invention, it is understood that this showing and description are illustrative only, and that I do not regard the invention as limited to the form shown and described,

or otherwise, except by the terms of the following claims.

I claim:

1. A carburetor comprising a fuel reservoir, a fuel pump connectedthereto, means for actuating the pump, resilient means for returning the pump to its inoperative position, and thermostatic means for limiting the return movement of the p p' "v 2. A carburetor comprising a fuel reservoir, a fuel pump, a movable cam having a series of depressions adjacent the pump, and means engaging the depressions coacting with the pump for controlling the action of the pump.

3. A carburetor comprising a fuel reservoir, a fuel pump, yielding means actuating the pump, a thermostatically actuated cam having a series 'of depressions adjacent the pump, and means engaging the depressions coacting with the pump for controlling the action of the pump.

4. A carburetor comprising a fuel reservoir, a fuel pump having a pivotally mounted actuating lever, yielding means actuating the lever, and a thermostatically actuatedcam adjacent the lever I adapted to limit the movement of the lever.

5.- A carburetor comprising a fuel reservoir, a fuel pump immersed therein, a pump operating member, and thermostatic means above the'fuel level coacting with the operating member for limiting the amount of fuel delivered by the pump.

6. A carburetor comprising a fuel reservoir, a fuel pump communicating therewith, a suction motor, a pivoted lever connecting the suction motor and pump, and a thermostatically actuated stop for limiting the travel of the lever.

7. A carburetor comprising a fuel reservoir, a fuel pump communicating therewith, a suction motor, a pivoted lever connecting the suction motor and pump, and a thermostatically actuated rotary cam for limiting the travel of the lever.

8. A carburetor comprising a throttle, a mixing chamber, a cylinder in communication with the mixing chamber on the discharge side of the throttle; a piston in the cylinder, a reciprocating fuel pump, an operative connection between the piston and pump, means for reciprocating the pump to discharge fuel, and thermostatic means limiting the movement of the piston to charge the pump with fuel.

9. A carburetor comprising a throttle, a mixing chamber, a cylinder in communication with the mixing chamber on the discharge side of the throttle, a piston in the cylinder, a reciprocating fuel pump, an operative connection between the piston and pump, a spring for reciprocating the pump to discharge fuel, and thermostatic means limiting the movement of the pump.

MILTON E. CHANDLER. 

